Underfeed stoker



.1 s. sx1-:Lw

'UNDERFEED STOKER .MME

wmvssses Figure 1. Fi

Patented im. 13, 192s.

UNITED sTATss PATENT oFFIcr-z.

' JOHN S. SKELLIY, OF IOXOIGAHIL .PE BIBYLVALNIA, ABBIGNOB T0 INTERNATIONAL CIBUBTIOH ENGINEERING OOEEORATION, A. CORPORATION QF DELAWARE.

l:YNIDEBFII'IED STOKEB.

.Application sued apn: as, 1921. serial no. 464,297.

To all wlwm it may-coment:

Be it known that I JOHN S. SKELLY, a citizen of the United tates, and a resident of Monongahela, in the count of Washington and State of Penney Vania, have made a new and useful Invention in Underfeed Stokers, of which. the following is a specification,

This invention relates to furnaces and particularly to furnaces in' which automatic means are employed for delivering fuel to the furnace and for' propelling 1t across fuel-supportin elements thereof.

An object o my invention is to produce a furnace of the type' s ied in which improved means are emp oyed for propel ling fuel through the furnace and for ef fectively'controlling combustion throughout the fuel bed.

A further object is to'produce`a furnace in which eective means are employed for controlling the depth and the contour of the fuel bed within the furnace.

These'and other objects, which will he made more apparent throughout the further description, are attainedby means of a furnace embodying the features herein 'described and illustrated. in the drawings accompanying and forming a part hereof.

In the drawings, Figure 1 isn diagrammatic .longitudinal sectional view o f a fur- "nace embodying my invention. Figure 2 is' a fragmental Asectional view illustrating a detail of construction employed in connection with the Stoker, such as illustrated in ingto Fig. l, illustrating a moditication of m invention, and Fign4 is a fragmentary p anv view of the ate bars forming the fuel supporting. sur ace.

The-furnace or Stoker illustrated is' simi lar in its general construction and in its gen# eral principles ofd operation to the Stoker illustrated and described in my application, Serial No. 398,897, tiled July 26,1920; It, however, embodies features which occasion a variation 1n its` operation and cause it to.

differ structurally from the 'Stoker illusf trated in said application. As illustrated, it includes a retort vwhich extends transf verse] across the frnt' of the furnace and to w ich fuel is' fed -by one or more lnech'nically-actuated plungers 6. The fuel fefl h v the plungers is received from one or f nately-a rc3 is a' view correspond- 'xnorchoppers 'i' located at the front of the furnace. Where several pluligers 6 are remployed they may be spaced along the retort. and may be operated by the same or by separate -operating mechanisms. Fuel propelled into the retort from the hopper passes 'across a plate 8 which forms the floor of the' retort and which is curved or inclined up wardly at its innemend, thereby forming' the 'lower portion o`f the rear wall of the retort. A

Fuel issuing from the retort traverses two series of grate bars i'n moving toward the rear .end of the u rnace. 'As illustrated, the.

first series of bars consists of alternately arranged moving bars 9 and stationary bars 9 located in parallel relation and extending from the retort downwardly toward the rear of the furnace. The forward ends 10 f these bars are so formed, and so' located and arranged, that they, in effect, formga eon' tinuation of the upwardly curved portion of the retort licor v8 and, therefore, forml the upper portion of the rear wall of the m tort.""`he rear ends of these hars overlap Sie forward ends of the second series o RTS. 'i

" The second series of bars consists of alter-r nged moving bars 11 and stationary .l arscllmlocatedwin parallel relation andfinclined downwatdl "iwl'lfthc rear end of the furnace. e inclination of these bars is preferably much less than that of the bars 9 and 9 and their rear cndsdischarge directlyinto the ash pit or well 12 which is located between them and the brid e wall 13 of the furnace.

sa v N The as i pit or well is preferably provided l ,with a clinker crushing and ash moving mechanism such as the ordinary clinker grinding rolls or a screw conveyor for :breaking up 'and -discharging cllinker ash fromthe furnace Asshown-in mounted on and, in effect, forms a "art of the framework of the'` stolzer., The' opper 7 is so arranged that itffeeds directly onto 'the forward .end of.th s` plate. and' the plunger 6, movingV parallel-tothe ua'centv portonof the late, propels the fuel rear# wardly across t e plate and through the .re-v

tort'onto the grate bars. The fuelfed across the plate Bt'ravcrses an expanding passage 1 4 as it enters' the retort proper.

' packing and insures the delivery of a' re Q Lea-asis and an upwardly and rearwardly mclinedi j or less loose mass of 'fuel to theretort@ 1 Asshown i'n the drawings, the' grate lbars7 I 9 and. 9 are hollow; each grate'bar being lower face and at' its forward end andan 9 and receivesea'ir from the passag livering' air inf adequate quantities' tov provided with' an air admission port 17 in its airdelivery-port 18 in its lower face at its 'rear end. The grate bars are so mounted on the frame portion of the stoker that the portsl? register with and'receive air under prcssureffrom an air conduit 19. 'The rear.' ends of .the bars 9 and 9 and so located and arranged that the air p'ortslS-` communicate with what' may termed a secondary -air chamber 20,. which is locatedbelowthe series 'of bars 9l and' are so mounted bars of each series and I have valso de-u scribed in detail meansl employed. for-holding the stationary bars in place on the framework of the Stoker.v Figure 2 illustrates a modificationof the means disclosed in said application for holding'the stationary'fbars 9' f the' first series in place. As here shown, the framework of the stoker -is provided with a stationary bar 27, the

upper edge'of which is engaged by downwardly-fprojecting lugs -28 formed on the lowr ace of eachfstationary/bar. The lugs-straddle the bar and in this way hold it .stationary duringl the reciprocations of the adjacent moving bars.l

ImFig. 3, I have'illusti'ated a.' modified form of' Stoker which is similar in'general details to the .structure i1ius'trate`-dv in Fig.

1. The bars 1 1 and 11" of the'V second 'f series aref however, 'so"forined" that 'they materially modify the distribution of fuel along the fuel-Supporting "surface and, consequently, thejfrcontour "of the fuel bed.

arranged that the fuel traversing them does Broadly speaking, these-grate' Vbars are so 'not move downwardly as'it movesfacross v their fuel-supporting surfaces. v 1nthe preafter. itflis'll assed th/rdugi tlf@ hollow ixr-fferred form' illustrated, the fuel-supporting terionof 'the ars;

Asrprcviously stated 'the'. forward' of'fthebars9iand -9 form'a continuation the fuelvas it 'issu'esl fromr the retort `and" as it first.- moves onto the grate bars 9 andv 9 ,'I haveprovided those bars' .11 of the second series. the nose or that portion of each bar which'.

with 'air delivery 'apertures 21'1ocated in -forms a continuation `of the retort wall, and also in-the forward end of the fuelsupporting' portion of 'each bar. The jarrangement 'o f 'the hars'fll and 1l shown in F igurev1"is similar to that shown in my above-mentioned coepcnding application. Air under 'pressure' is delivered to these bars through inlet )Orts 22 which regist'erwith the upper enti of a delivery conduit 23. These bars are also provided in their fuel supporting surfaces 'with air. delivery. apertures 24avhich 'are located adjacent `theV forward ends of the bars. The lower yface of each` bar is rovided with an air de-5 livery port 251wluch discharges into achamber 26 locatedbelow the series ofbars. In this case,v as in the case of the bars 2L), the air so discharged is preheated in its passage through vthe bars and then isA delivered to' the fuel=`bed through the spaces between the bars.`

"ln my co-pendingapplication I have described the means-employed for imparting a rcciprocatory inotion to the moving grate surfaces of the -bars 11 and 11 are ,in chnedupwardly from the horizontal sothat the. fuel traversing them is actually elevated A as' it passes across them toward the ash pit.-

or `well 12. Vith this construction, the tendency of the fuel bed to thiny vout to- 4ward the-rear of the furnace is materiallyA `decreased and,` as .a matter of 5" -1ct, there is a tendency; for the fuel'bed to thicken at the point where the fuel issues from the bars 9 and 9 onto the bars` 11 and The air distribution-in the stoker illustrated in Fig. 3`is similarl to that of theA the hoppers 7 into the retort 5. It will, of

course,- be understood that the fuel'is, in effect, crowded into the retort by oncoming fuel und `in this` way is delivered onto'the grate bars 9and 9. AThe reciprocation of the moving grate bars 9 not only operates to break up thefuel bed supported by the The-bars of bars and the mass of fuel issuing from the retort, but alsov operates to propel fuelf dou'nwaidly alongtle bars. The reciprocation of the inoringburs l1 alsofpropels' the fuel rearwardly toward the Well-12 and breaks up the portion of thefuel bed supported by them. The delivery of air to the fuel lied is substantially as described in my messie (1o-pending application es there storied, is such es io maintain zones of increased. combustion along the :incl hed. l,

lfhe operation of the stolzer shown in lig. 3 is substantially similar to tliet'inst de scribed except Athat the upward tilting or the grate hers 1l and 1l occasions s, 'piling np of the fuel on these liars and consequently increases the everege thickness of the fuel bed and 'varies its contour throughout the furnace.

While l have described init two embodi ments of my invention, it will he apparent to those slrilled in the -zirt vorions changes, modifications, additions ondoinissions may he nicole-'in the eppsretus illustrated without departing from the spirit and scope of my invention, es set forth hy the appended claims.

' ll claim es my invention:

l. ln combination with ,o furnace, e stolzer comprising n transversely extending retort located et the foi-word end ol' the furnace, n 4floor lor the retort elevated at its resi? or fuel delivery edge, n series of spaced, downwardly inclined, alternately arranged, inov-- nog and stationery grate hars located in 'pen lcllel relation ond extending from the retort toward the reerfozf the urnecc, esch -ibar having s Wedge shaped forwsrd end so arrsnged es to form en extension of lthe incl delivery-.side of the retort and having apertures formed in the ripper :fece thereoi2 and 1n seid Wedge shaped forward j end, means 'or delivering air under pressure through seid apertures and through the spaces between the here, o second series of spaced, alternately arranged, moving and stationary grate bers located in parallel relotion, overlapped st their 'lorwsrol ends by seid first series and extending toward the rear of the furnace at :i meter-lolly differ'- ffent inclination from that oiE the hars of seid tiret series, each oor olf seid second series having; apertures formed in 'the upper fece near the forward end thereof and means for delivering cir under pressure through said apertures sind through the spaces between the bers o said second series.

2. ln combination with e furnace, n Stoker including o retort extendin across the front of the l'nrnace and provi ed with e substantially flat ldoor inclined upwardly et its rear or fuel delivery edge, e series of word end sic-arranged es to form en extension of the incl delivery si de of the retort and heving apertures formed in the upper foce end in seid Wedge shaped forward end thereof, a second series of spaced, alternately or ranged, moving and stationery grote hers located in parallel relation and overlap ed by the rear ends of the 'liars of the rst. series and extending toward the rear of the furnace at o materially dierent inclination from the hars of the first series, @zich of saidsecond series ol. bars having apertures formed in the upper face thereof and means for delivering oir under pressure thron h seid apertures and through the spaces ctvveen the bars. y

3. .ln combination with a furnace, stolzer including a retort extending lacross the :front of the ini-nace and provided'with a substantially liet floor inclined .upwardly at its rear or fuel delivery edge, a series of spaced, downwardly inclined, alternately arranged, moving and stationery grote bers located in parallel relation and extending from seid retort toward the rear of the furnece, each her havin o, Wedge shaped forword end so arrange es to form an extension of the fuel delivery side ofthe retort sind having onertures formed in the upper fece ond in sind Wedge shaped forward end thereof, o second series 'of spaced, elternstely arranged, moving and Astoti'olntry grate bars located in parallel relation and extending `toward the rear of the furnace at o, materially di'ereglt inclination Afrom the bars of the first. series, each of said second series of bars having apertures formed in the upper face thereofandinesns for delivering air under pressure thron h said apertures and through the spaces @tween` the bars.

In testimony whereof, I have hereunto subscribed my name this QOthdey of April, 1921.

JOHN s. sinonimi.

Witnesses:

E. C. LEM-mns', J0. l?. Bownnr. l 

